I wanted to end it that way, actually, but I didn't really liked it. The Foundation sent a document about the human story because they thought that there really was a civilzation of intelligent turkeys, but instead they found turkey-eating alien birds.

…So do the inhabitants of the turkeyverse know that turkeys are actually native to the New World, and the name "turkey bird" derives from the fact that the Turks were the first Europeans to domesticate and trade them?

Not really. They know nothing about our turkeys. The ancient Hindler turkeys talked Turkish, but then the Herons came over and ate them all. Now they are trying to trick the turkeys from another dimension to think that there is a turkey heaven. Legit enough?

This is hilarious [sans the few typoes]. Reminds me of Hitchhikers' Guide To The Galaxy without being overly silly or going into LOLFoundation territory. You played the tone straight and for that, bravo. Hope this gets mainlisted.

The way this is worded makes it sound as if it was already explored when we found it. Do you mean "partially explored"?

Unlike most similiar phenomena currently contained by the Foundation,

You don't need to establish that your SCP is special; you might want to take this out.

SCP-XXXX extends in three dimensions and constantly emits a bright pink light.

Did you mean to say that the anomaly isn't just a flat object? I'm not sure what you mean by including that.

SCP-XXXX is unaccesible to most living beings, with the exception of specimens of Meleagris gallopavo (Wild turkey).

*inaccesible.

Monthly, SCP-XXXX will undergo into an expansion event.

*undergo an

SCP-XXXX has reached a stable dimension

What does this even mean?

Instances of SCP-XXXX-1 are, per se, to be considered not anomalous

This is untrue, because it was created through an anomalous method.

All the materials wich instances

Typo with "wich"

All the materials wich instances of SCP-XXXX-1 and their contents are composed appear to be identical to the ones found on Earth.

And this whole sentence is a conglomerate of random words.

Instances of SCP-XXXX-1 can be opened without any difficulty by standard machineries

What's a standard machine?

wich at the same time contain itemes of different nature,

This is worded strangely and you have two typos in here. (Wich and itemes)

eferred by SCP-XXXX-2 as

You should explain what -2 is earlier after mentioning it.

despite it has never referred to itself or other individuals as such.

"Despite the fact that is has never…"

SCP-XXXX-2 has so far comunicated

Take out that "so far"

and sent trought SCP-XXXX during an expansion event without accident.

*through, and didn't you say that we could only send turkey's through and not other materials? Might want to add that.

On the background was visible what could or could have not be a city.

"What appeared to be a city was visible in the background" or something like that

Instances of SCP-XXXX-1 have since stopped emerging from SCP-XXXX. SCP-XXXX is slowly decreasing in size, with a rate of [DATA EXPUGNED].

Yah spelled expunged wrong. And I think it would make more sense to black box or redact it.

Final Verdict

A turkey portal shaped like a turkey, sending turkey artifacts from a turkey dictatorship(?). I enjoyed it, though I'm questioning why they killed poor Mr. Gobbles. Why send a turkey house in the first place? Did they kill him because they defeated the Herons?

I enjoyed it, and I especially like how the portal started to shrink in the end. It left a nice sense of satisfaction, with the turkeys saying "welp we're done with these guys, moving on".